|DESAULNIERS, AMY - University Of Nebraska|
|LEE, CHANHO - University Of Nebraska|
|WHITE, BRETT - University Of Nebraska|
|FORD, JOHNY - Retired ARS Employee|
Submitted to: Animal Reproduction Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/15/2015
Publication Date: 8/1/2015
Publication URL: http://handle.nal.usda.gov/10113/61170
Citation: Thorson, J.F., Desaulniers, A.T., Lee, C., White, B.R., Ford, J.J., Lents, C.A. 2015. The role of RFamide-related peptide 3 (RFRP3) in regulation of the neuroendocrine reproductive and growth axes of the boar. Animal Reproduction Science. 159:60-65.
Interpretive Summary: Pigs are selected for high growth potential, which can have negative consequences for reproductive performance. The hypothalamus, located within the brain, controls growth and reproduction by regulating secretion of hormones from the pituitary gland called growth hormone and luteinizing hormone, respectively. How this occurs is not well understood, but is known to involve hormones from the hypothalamus called neuropeptides. Scientists examined a neuropeptide called RFamide-related peptide 3 (RFRP3). They discovered that RFRP3 regulates secretion of growth hormone but not luteinizing hormone in male pigs. This discovery is an important step toward understanding how to select and manage pigs for high growth rate without negatively impacting secretion of reproductive hormones.
Technical Abstract: RFamide-related peptide 3 (RFRP3) has been implicated in the regulation of the male reproductive and growth axes. However, responsiveness to RFRP3 appears to be dependent upon sex, specie, physiological status, and developmental stage. Our objective was to evaluate the effects of RFRP3 on circulating concentrations of luteinizing hormone (LH) and growth hormone (GH) in mature boars. We hypothesized that RFRP3 would reduce circulating concentrations of LH and increase concentrations of GH. Mature, intact Meishan boars (716.6 ± 2.8 days of age; 125.0 ± 12.4 kg BW) were fitted with indwelling catheters for blood collection and intravenous treatment. Boars were randomly assigned to treatment: saline (n = 4) or RFRP3 (8.5 mg; n = 5). Plasma was collected at 15-minute intervals during 3 periods: pre-treatment, treatment, and post-treatment. During the treatment period, saline or RFRP3 in saline were administered at 15-minute intervals. Treatment was administered as a loading dose of 5 mg RFRP3, followed by 7 repeated injections of 0.5 mg RFRP3. Challenge with RFRP3 failed to alter (P >= 0.36) concentrations of LH or GH during the treatment period. However, RFRP3-treated boars had reduced (P = 0.03) concentrations of LH during the post-treatment period when compared to saline-treated boars. Administration of RFRP3 increased (P = 0.02) mean concentrations of GH during the post-treatment period when compared to saline-treated boars. It is concluded that RFRP3 does not act to suppress LH secretion in the boar, but that it may function in regulating the growth axis.